Metallurgical furnace.



u. wenas.' METALILURGICAL FURNME.` APPLICATION `FILE!) OCT. 22, I`9'I'3. 1

' 3 SHEETS-SHEET l.

Unrrnn srArEs P UTLEY WEDGE, or Annivronn, PENNSYLVANIA.

Original application filed February 25,

serial No., 750,596, and Februar-.v 25 1913? of which the following is a specification.

The object of my invention is to provide for the effective heatingof thehearth of a metallurgical furnace bynleans of an electric current. y

In the accompanying drawings I have illustrated the application of my inventionA to a furnace of the superposed hearth type intended especially for laboratory use' and.V

.rotating having alternating iiXed and hearths, but this is simply for convenience, as my invention is not-limited in its application .to furnaces of this type. In the drawings: Figure 1 represents a vertical sectional view of a furnace constructed in accordance with .my invention; 'Fig 2 a horizontalgsetional, View on the line L -a, Figjl; Fig. "3 a transverse vertical section onI lthe line bvb, Figr2; Fig. 4 a horizontal section of a modified typeof furnace, and Fig. 5 a transverse section on the line c-0, Fig. 4.

In Fig. 1 of the drawing I have shown a furnace havingnine hearths numbered consecutively from top to bottom of the furnace, the hearths 1, 3, 5, 7 and 9 being fixed hearths mounted in the outer wall of the furnace and the hearths 2, 4, 6 and 8 being rotating hearths which are carried by a central shaft 10 mounted in a 'suitable stepbearing kb eloiv. thel furnace' and intended to be rotated .by any suitable mechanism, preferably of such character that the speed of rotation ofthe shaft can be changed at will. The furnace may, however, have agreater or less number. of hearths than `I have shown. i v The shaft 10 is preferably hollow so as to permit of the circulation of a cooling medium through it and it is surrounded by relatively shortsleeve sections '11 interposed between the successive rotating hearths so as to aid' in the support of the 5.21.1119, Said sleeves being composed of irebrick, tile, or other .heat-resisting material, in order to protect the shaft from injury by the high temperatures which may have to be main- Specifcat'ion of Letters Patent. y Patented Apr. 27, 1915.

1913,- Serial No. 750,596. Divided and this application filed October 22, 1913. Serial 110.796,609. .Y

tained within the working chambers of the furnace.

Theouter wall of vthe furnace isi'com-A posed of rings 12 of tirebrick, tile, or other refractory material, made either in one piece or in sections, and interposed between the successive fixed hearths of the furnace whereby the building up of a furnace structure having a closed casing can be effected expeditiously and with smallv expenditure of time and labor. In order to restrict as much as possible the radiation of heat from the` furnace, the outer wall ofthe same is provided` with a coating or covering 13 of magnesia, asbestos, cement, or other material which is a non-conductor or a poor conductor of heat, and in order `that this covering may adhere firmly to the wall of the furnace the rings 12 of the-same and also, if desired, the outer faces of the fixed hearths may be-roughened, toothed or corrugated, as shown in Fig.' 2.

. rI`he lower-most of the rotating'hearths of the furnace, is mounted upon a flange or collar 14 on the shaft 10 and where said shaf passes through the top and ,bottom fixen hearths it is provided with luted jointsl to prevent the escape of gas from the interior of the furnace at these points. The top hearth of the furnace may conveniently be used as a drying hearth, the material bcing fed inwardly over the saine by means of rabbles 16 carried by rabble arms. 17 secured to and projecting from the upper pory tion of the shaft 10, the material being fed' from the drying hearth 1 onto the first rotating hearth 2 through the upper luted joint 15 and the course'of the material in its passage through the furnace being-then outwardly on the rotating hearths and in.

Wardly on the stationary hearths, the rotating hearths being less in diameter than vthe interior of the furnace and the stationary hearths being provided with central openings 1'8 of greater' diameter than the sleeves 11 in order to permit of the dropping of lthe `material from hearth kto hearth.. In order to provide for such movement of'the materia-l over Athe hearths, rabbles are provided, these rabbles having stems 'supported in rabble holders which are mounted in openings on the fixed and rotating hearths and extend belowthe same so v'that the-rabble stems can be readily applied TENT orFicE.

ion

liearthjs of the furnace and it may be used' inf connection with ordinary furnacesy hav-- ing super'posed-ffi'xed hearths or even `but a single hearth,1 insome cases.

Eig. 1 of' the drawingg-the electrical heating 'devices are shown as applied to the liearths A3', `5 and 7. Each of these hearths has sector-shaped .recesses or chambers,. as shown in Fig. 2, forthe reception of e ec'- trical resistance lblocks 2l, each recess being closed attheftopdn order to provide a kcon inuous upper surface for the hearthbut b ei'ngppen below in. order that the heat may beradiated `from the resistance block directly upon the material carried by the resistance block the recess or chamber in which it is containedmay have at each side a flange or shelf 23, or other means of support' may be provided asdesired. Current can be'supplied to the resistance block in' various Ways soas to efectthe heating ofthe latter bythe passage ofthe current.

through it. rhe block may have a hollow ogre 24 of electricalinsulating material for t e reception of the Wire from one terminal of the electricgenerator, this Wire being in electrica-l connectionwith the inner end of theblock 21 and the 'Wire or Wires from the f other `ftermin'albeing in connection with theouter end ofsaid block, or the block may lhave an openingl. of larger diameter than theconducto'r which is centrally supported in 'the opening by ,any desired insulating means, or the (block may be composed of separated sections'-and the conductor may occupy aposition midway of the space .between them` allI 'of th'ese constructions being' shoumV in v`Fig. 2. shape of'fth'ei`| resistance blocks in a hearth maybe varied as desired without departingfrom my inventionor the hearths may 'consistjmainly of a series of such resistance block sf moun ed at vtheir opposite ends in the Wall str cture,as shown for instance at 2 6 infFigwl, each block being connected at one end to one terminal of the electric generator and at the .opposite end to the other, terminal 'ot the same, and the blocks ruary 2,5, 1913, 'and of which this applica-1 The number. and' being, if desired, insulated from one an- U0 other as, for instance, by an electric insulating material inserted between them, the upper faces of the blocks being covered with a layer 27 of refractory material to provide a proper hearth surface heated from below but the blocks' being exposed on their under surfaces so as to radiate heat directly upon the material on the hearth beneath.

In' a'furnace of the type shown in Fig. 4

`the hearth may have a central strip 28 of tile or irebrick for carrying the rabble holders 20.

I claim: 1. In a metallurgical furnace having a plurality of superposed hearth's, a hearth 75 on the hearth below.

2. A metallurgical furnace .having Va hearth with electrical resistance body therein, andv anelectrically insulated'conductor passing through said body and 'in electrical connection with the inner portion thereof. hearth beneath. In order to support each '3. A metallurgical. furnace having a S5 hearth com o's'ed of aplurality of Sections disposed si e by side, electrical resistance bodies' in some of said sections, and rabbles carried by sections alternating therewith.

4. A metallurgical furnace having a J0 hearth with open-bottomed recess' therein,

'an electrical resistance body contained in said recess and exposedn the under side, and means for passing' a currentv of elece tricity through said-resistance body so as to heat the same.

5. A metallurgical. furnace having a hearth with sector-shaped recess therein, a sector-shaped electrical resistancebody,

adapted to sai-d recess, and means for paSs- .100 lng a current of electricity through sald re- 'sistancebody so as to heat the same.

6-.' A metallurgical furnace having' a hearth with recess therein, an electrical resistance body contained in ysaid recess, lan electrical vconductor passing through said resistance body from the outer to the inner portion ofthe same, and means Vfor insulating said conductor from saidresistance body except at the inner portion of the latter.

In testimony whereof, I have signed my name to this Specification, in thepresencsof twoy subscribing Witnesses.

UTLEY WEDGE;

-Witnesses:

KATE- A. BEADLE, HAMILTON D. TUnNER.' 

